Rework repair logic

internal/torrent/util.go

@@ -2,14 +2,15 @@ package torrent
 
 import (
 	"fmt"
+	"strings"
 )
 
-func getFileIDs(files []*File) []string {
+func getFileIDs(files []*File) string {
 	var fileIDs []string
 	for _, file := range files {
 		if file.ID != 0 {
 			fileIDs = append(fileIDs, fmt.Sprintf("%d", file.ID))
 		}
 	}
-	return fileIDs
+	return strings.Join(fileIDs, ",")
 }